This invention pertains to implantable medical devices and to methods and systems for operating same. In particular, the invention relates to means for communicating with such devices.
Modern pacemakers typically have the capability to communicate data via a radio-frequency link with an external programming device. Such data is transmitted to the pacemaker in order to program its mode of operation as well as define other operating parameters. Data transmitted from the pacemaker can be used to verify the operating parameters as well as relay information regarding the condition of both the pacemaker and the patient. Pacemaker patients are monitored at regular intervals as part of routine patient care and to check the condition of the device. Among the data which may typically be telemetered from the pacemaker are its programming parameters and an electrogram representing the electrical activity of the heart as sensed by the pacemaker. Pacemakers have also been developed which monitor certain parameters over time while the device is functioning in the patient. Data representing these parameters can be stored in memory for later retrieval using an external programmer.
It would be desirable in certain situations to be able to communicate with an implantable medical device such as a pacemaker without the need for an external programming device or any kind of equipment such as a radio transmitter/receiver. This would enable a patient, for example, to alter the operation of the device by such communication at any time or place as the need arises. Furthermore, the data recording capabilities of the implantable medical device could be activated by the patient whenever subjective symptoms are noted. The recorded data could then be retrieved later and analyzed for correlation with the symptoms experienced by the patient.
Accordingly, in one embodiment, the present invention is an implantable medical device, such as a cardiac pacemaker or implantable cardioverter/defibrillator, having incorporated therein a system enabling voice communication with the device so that the device responds to voice commands. The system includes an acoustic transducer and processing circuitry for sensing a patient""s voice and deriving messages from words spoken by the patient, which messages may then alter the operation of the device. When a patient in whom the device is implanted speaks, the vibrating chords of the larynx cause acoustical energy to be radiated into the thorax where the acoustic transducer converts the energy into electrical audio signals. The audio signals can be analyzed with speech recognition circuitry to recognize certain words that correspond to system messages which are then employed to affect the operation of the device. In certain embodiments of the device, the patient""s spoken commands can be used to alter the operating mode of a pacemaker, change operating parameters, or initiate recording of physiological data for later retrieval. Such recorded data can include, for example, electrograms, recordings of the patient""s voice, heart sounds, respiratory patterns, or indications of physical activity.
In another embodiment, the invention is an implantable medical device, such as a cardiac pacemaker or implantable cardioverter/defibrillator, having incorporated therein a system enabling voice recording by the device, with the voice recording activated by either an external or internal signal. In the case of externally activated voice recording, the external signal may be, e.g., a voice, tactile, or magnetic signal imparted to the device by the patient or physician. An internal signal may be generated by the device upon sensing a particular physiological condition via its sensing channels, where the particular condition would typically be defined as one where it would be useful to have the subjective impressions of the patient while the condition is present, such as during an arrhythmic episode.